As the value and use of information continues to increase, individuals and businesses seek additional ways to process and store information. One option available to users is information handling systems. An information handling system generally processes, compiles, stores, and/or communicates information or data for business, personal, or other purposes thereby allowing users to take advantage of the value of the information. Because technology and information handling needs and requirements vary between different users or applications, information handling systems may also vary regarding what information is handled, how the information is handled, how much information is processed, stored, or communicated, and how quickly and efficiently the information may be processed, stored, or communicated. The variations in information handling systems allow for information handling systems to be general or configured for a specific user or specific use such as financial transaction processing, airline reservations, enterprise data storage, or global communications. In addition, information handling systems may include a variety of hardware and software components that may be configured to process, store, and communicate information and may include one or more computer systems, data storage systems, and networking systems.
An information handling system may include a number of direct current to direct current (DC-DC) voltage regulators that provide regulated voltages to different loads. The load current may vary across a broad range from relatively high peak currents to very low stable currents. From power efficiency perspective, voltage regulators may be required to maintain a high efficiency or low power loss over such current ranges. A voltage regulator may include a controller, one or more drivers, and one or more phase power stages. Furthermore, a phase power stage may include on inductor, one or more metal-oxide-semiconductor-field-effect-transistors (MOSFETs) as switches, which may be driven by the MOSFET drivers.
The DC-DC converters used in voltage regulators implemented in servers typically should be designed for a large range of server configurations. The DC-DC converters in the voltage regulators of these servers generally need to be designed to handle the full load of the server safely, and also need to be optimized for efficiency, size, and cost. Additionally, in multi-phase voltage regulators that use a diode as an inductor freewheeling switch, the load can drop such that the voltage regulator enters a discontinuous current mode (DCM), which is caused when the instantaneous current in an inductor of the voltage regulator drops below zero amperes. The voltage regulator may enter to negative current operating mode if a MOSFET is used as a synchronous switch for inductor freewheeling, because a MOSFET has bi-directional current conduction capability. The negative current can cause additional power loss by a reverse current flowing through the inductor and a low-side MOSFET. A technique known as diode emulation can be implemented to reduce these losses in the low-side MOSFET and the inductor. Diode emulation is performed when the low-side MOSFET is turned off as the current reaches zero, and the current is prevented from circulating in the DC-DC converter.
The use of the same reference symbols in different drawings indicates similar or identical items.